Prior art magnetic tape data storage is typically used for data backup, data archiving, and/or data processing purposes. In the art, magnetic tape media is known as a convenient, cost-effective means of storing large quantities of data. Often, magnetic tape media is employed in the form of tape cartridges (sometimes referred to as tape cassettes). Tape cartridges generally comprise a length of tape media which is supported on at least one reel which, in turn, is rotatably enclosed in an outer casing. The tape cartridge configuration allows convenient handling and storage of the tape media. Additionally, the tape cartridge configuration facilitates automated handling of the tape.
Modern magnetic data storage tape handling systems typically include a plurality of tape drives as well as an automated data storage library. Each of the tape drives is configured as a sub-system which is configured to read data from, and/or write data to, the magnetic tape. The automated data storage library typically includes a storage rack or the like having a plurality of storage slots or the like for supporting a large number of tape cartridges. The data storage library also typically includes a robotic accessor such as a picker arm or the like which is configured to move tape cartridges from the respective storage slots to a given tape drive. Additionally, typical libraries often include at least one reader which is configured to read the contents of the cartridge memory.
An example of a typical tape handling system which includes a plurality of tape drives as well as an automated data storage library is disclosed in U.S. Pat. No. 6,172,833 B1 to Fry et al, and which is incorporated herein by reference. A similar tape handling system is available from the Hewlett-Packard Company of Palo Alto, Calif. The tape drives of such tape handling systems are typically configured to be in signal communication with data processing equipment or the like which generates and/or processes data. Data processing equipment can include, for example, large mainframe computers or the like, or local area networks comprising a plurality of PC's or workstation computers.
Typically, data is sent to, and/or requested from, the data storage handling system by the data processing equipment. That is, the data processing equipment alternatively either sends data to the tape handling system to be written to a tape, or requests that the tape handling system retrieve certain data from a given tape. The data storage handling system then carries out commands issued by the data processing equipment by either writing data to, or retrieving data from, the appropriate tape cartridge.
As disclosed by Fry et al, tape cartridges which are configured to be used in conjunction with the tape handling systems such as those discussed above, typically comprise a memory device such as a memory circuit or the like, which is mounted on the casing of the tape cartridge. Such a memory device is often referred to as a “cartridge memory.” The cartridge memory typically comprises a memory circuit module, such as an EPROM semiconductor memory chip, which is mounted on a circuit board or the like.
The cartridge memory, although relatively small, can be used for storing many types of information such as condensed versions of block maps or indexes of the data stored on the associated magnetic storage tape. However, the cartridge memory is typically employed to store “label information” regarding the associated tape cartridge. Label information can include, for example, the serial number of the tape cartridge and the type or category of data stored on the tape cartridge. In many cases, when a given tape cartridge is accessed by a tape drive so as to have data written thereto, the tape drive updates some of the information which is stored in the cartridge memory of the given tape cartridge.
The data storage library also typically conducts “inventories” of each of the tape cartridges by sequentially accessing and reading the entire contents of the cartridge memory of each of the tape cartridges. This is often performed by the automated picker arm of the data storage library. One of the purposes of such an inventory is to ensure that the data contained in each of the cartridge memories is also contained in the memory of the data storage library.
That is, the data storage library includes a memory which is configured to store the information which is contained in each of the cartridge memories. This allows the data storage library to display the information on a display screen, and/or allows the data storage library to make such information available to the data processing equipment. For example, the data processing equipment can query the data storage library asking if a given tape cartridge is available.
However, the process performed by the library, wherein the process comprises reading the entirety of each of the cartridge memories, can require a considerable amount of time and processing resources. What is needed then, are methods and apparatus which achieve the benefits to be derived from similar prior art devices, but which avoid the shortcomings and detriments individually associated therewith.